This invention relates to an apparatus for making a number of sliced portions of specific weight from a cuttable product, more particularly for making one-pound cut-bread portions for packing from loaves.
Devices of this kind, particularly for cutting foods such as bread, cheese, sausage and meat products etc., are used, for example in installations for making cut bread up into portions.
In the installations of this kind on the market, loaves of a length of about 1.1 m are fed by a feeder to a cutter which cuts the loaf into slices of a specific thickness.
Cutting is usually carried out with a sickle-shaped or circular blade which rotates at a speed of about 500 rpm and more about the blade axis and accordingly cuts some eight or nine slices per second.
The cutter blade or cutter blade shaft is usually driven by an electric motor via an output shaft on which a first gearwheel is fixed, which meshes with a second gearwheel which is in turn connected to the usually epicyclic cutter blade.
The above two gearwheels are also interconnected via a crank so that the superimposition of the two movements arising out of the above-described structural features produces a rotary movement on the one hand and a planetary movement on the other hand for the cutter blade about the cutter blade shaft.
The feeder supplying the product--i.e. the loaves in the case of a cut-bread batching device--to the cutter unit preferably engages the product positively to prevent the product from receding when the cutter blade engages it, and to ensure uniform slice thickness, and is accordingly preferably constructed as a spiked chain or the like.
In machines of this kind on the market, the slices are carried off by means of a conveyor, the conveying speed of which--like the conveying speed of the feeder--is usually controllable, in order thus to provide a buffer effect and keep the cut slices in mutual contact.
The conveyor for carrying off the portions is usually attended by an operator who rejects the crusts at the beginning and end of each loaf as being unusable for the portions.
The operator also takes a specific number of slices for packing--e.g. some 10 to 13 slices for a one-pound portion--and also is required to check the total weight of the resulting portion on a weighing machine. If the weight is below the predetermined portion weight, then the operator will add one or two slices to the portion. If, on the other hand, the portion weight recorded by the weighing unit is above the predetermined required weight, the operator will remove one or more slices from the pile.
The portion consisting of the slices of bread is then placed on the actual conveyor for carrying the slices off or placed in a box thereon and conveyed to the packing station.
It has been found in practice that the operators frequently omit the weighing operation and rely simply on "feel" or their experience as to how the portion looks in respect of the required weight. Consequently, the individual portions of bread frequently have considerable differences in weight, overweight generally being involved in view of the regulations, because underweight portions must be avoided under the statutory provisions. This recurrent or very frequent overweight means considerable losses for the baker, because the price of the portion is calculated according to the intended weight.
The literature also discloses a device of the above-described type in which the required weight of a portion is varied by way of the slice thickness either instead of or in addition to by way of the number of slices. When the portion weight or part portion weight resulting from a specific number of slices is reached, the weighing unit transmits it as an actual value to a comparator, which also receives the set-value and which in turn acts on the speed of advance of the conveyor--via a separate control system if required--and either increases or reduces it according to the actual value signalled, in order thus to increase or reduce the thickness of the slice and hence provide a correspondingly corrected portion actual weight.
The disadvantages of the first apparatus described and of the method which can be performed with this known apparatus have already been indicated above and are obvious so that they need not be discussed in detail here. We will simply point out briefly that the known device is relatively expensive as regards its operating costs in view of the personnel required, while in addition its output is relatively limited, because an operator can of course only achieve a specific capacity. This is the reason for the inaccuracy already indicated above and the resulting cost. In addition, this known method of operation is not very hygienic in view of the use of the operator's hands.
With regard to the second known method described, in which the slice thickness is variable to obtain the most accurate possible portion weight under the control of the weigher unit, no apparatus has hitherto been disclosed for performing this method to satisfy the requirements in respect of operational reliability, handling of the product, slices and portions etc., while at the same time giving a high output equivalent at least to the cutting capacity of the cutter unit with which it is today possible, as already indicated above, to produce eight or more slices per second in the case of a loaf as the product. With other products the cutting capacity is even considerably higher in some cases.
To perform the second method described above, with a variable slice thickness, the literature has suggested a piling unit which collects or piles the cut slices on a paddle and then places the pile on a conveyor for carrying off the portions when the cutter blade of the cutter unit has cut the last slice of the portion and it has been placed on the pile. The piling unit together with the paddle is disposed on the weigher unit.
A disadvantage of this apparatus proposed in the literature is that the collecting or piling and the subsequent placing of the slice portion on the conveyor by means of the paddle cannot be carried out with sufficient speed, so that this part of the apparatus is a bottleneck in comparison with the cutter unit and prevents the otherwise attainable capacity of the apparatus from being achieved.
A further disadvantage of this known system is that the cut slices fall or tip on to the paddle. In the case of products such as bread or meat etc. this means that the slices making up the portions are not piled flush with one another in the way required or at least highly desirable for subsequent packing.